Motor-controller.



U. T. EVANS.

MOTOR CONTROLLER.

APPLICATION FILED MAY 14, 1910.

1,108,563, Patented Aug.25,1914.

ms. JW v &Lun 1% gla erzoem an si UNITED STATES PATENT OFFICE.

CLARENCE '1. EVANS, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER HA GONSIN.

' MFG. 00., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WIS- MOTOR-CONTROLLER.

Specification of Letters Patent.-

Patented Aug. 25, 1914:.

Application filed May 14, 1910. Serial No. 561,408.

connected to sources of sup ly from which they are liable to receive ainormally high volta e. V i

It is the principal object of my invention to provide means for protecting such motors uaon abnormal increase in voltage, prefera ly by disconnecting the motor from circuit.

A further object of my invention is to provide means whereby when the motor circuit has once been opened upon the occurrence of abnormally high voltage, it cannot be closed until the line volt-age is restored to a safe value.

A still further object of my invention is to provide protective means which will positively and promptly return to normal position when the normal volta e is restored.

Various other objects an advantages of my invention will hereinafter be clearly set forth.

For the purpose of more clearly disclosing the nature and characteristic features of my invention, I shall describe the controller diagrammatically illustrated in the accompanying drawing, which embodies my invention in one form. It should be understood, however, that my invention is susceptible of various modifications.

For the purpose of illustration, the contreller has been shown in a simplified form, the same merely consisting of a main switch 1, an accelerating device 2 and a relay switch 3. The main switch 1 is provided with an operating winding 1 and an auxiliary contact 1". In practice, the switch l'may assume any preferred form. As illustrated, the accelerating device 2 comprises a pivoted arm 4, movable over a series of contact buttons 5, and connected to the plunger (3 of an operating winding 7 The device .2 is adapted to control an armature resistance 8. It should be understood, however, that any preferred accelerating or starting device or devices might be employed in lieu of the device just described. The relay switch 3 may be of any preferred type. .As illustrated this switch normally stands in closed position, and is arranged to be operated by an electromagnetic winding 3*, having a movable plunger connected to said switch. The relay switch is also provided with an auxiliary or lamp switch 10 tending to stand in closed position and adapted to be opened by an extension of the plunger of the winding 3, when said winding responds to lift the relay switch. The'functions of the relay switch 3 will be hereinafter fully described.

While my invention embodies certain features applicable to various different types of motors, it is particularly desi 'ned for shunt wound motors, and I have, therefore, shown the apparatus above described as controlling a motor 11, having an armature A and a shunt field winding F. In practice, where shunt wound motors are subjected to abnormal increases in voltage, the same are wholly incapable of protecting themselves, and it is to atlord due protection thereto that my invention is particularly directed.

For accomplishing the most desirable results, I prefer to connect the operating winding of the relay switch directly across the terminals of the motor armature, through the lamp switch 10, and in addition, to connect one terminal of the operating winding 3'9, to one of the main lines, pref erably the positive line through a suitable resistance 12. The circuit connections for the relay switch and the function of the resistance 12 will be hereinafter more clearly set forth.

I shall now describe the operation of the controller, at the same time clearly setting forth the circuit connections therefor. Let it be assumed, that current is supplied to the operating windings of the controller, from main lines 13 and 14 through a main line switch 15, a manual control switch 16 being provided to start and stop the motor, at will. To start the motor, the control switch is first closed. This completes a circuit from main line 14 through the main line switch 15, thence through the switch 16 and theoperating winding of main switch 1 by conductor 17, througi the relay switch, 3 by conductor 18 to main line A. There: upon, the main switch 1 responds to complete the motor circuit, which may be traced from main line 13 through main switch 1 by conductor 19 to a point at which the current divides, part passing through the shunt field. winding F by conductor 20 to main line 14-, and part oassing through armature A by conductor 21 through the controlling arm of the accelerating device 2, thence through the resistance 8 to mainline 14-. The motbr is thus started, but at a slow speed, owing to the insertion of the resistance 8 in the armature circuit. However, main. switch 1, upon closing, completes through its auxiliary contact 1', a circuit to the operating winding of the accelerating device 2. This circuit may be traced from the auxiliary contact 1 of the main switch 1 by conductor 22 through the operating winding 7 by conductor 23' to main line 14-. Thereupon the; arm 4i is drawn up over the contacts 5, thereby gradually removing the resistance 8 from circuitQ ihis gradually brings the motor up to normal speed As previously set forth the operating winding 3 of the relay switch is connected across 1e terminals of the motor armature. This connection is made from one terminal of the motor armature by conductor 24 through the lamp switch 10, thence through the operating Winding of the relay switch by conductor 25 to the opposite terminal of the motor armature. Also, one terminal of the operating winding 8' of the relay switch is connected by conductor 26 through the resistance 12 by conductor 28 to main line 13. The mode of operation and function of the relay switch is as follows: So long as normal voltage prevails, the relay switch will remain in the position illustrated, thereby completing the circuit through the operating winding of the main switch. Should, however, the voltage rise above a safe value, the counterelectromotive force of the motor would increase to such an extent as to cause the relay switch, when properly adjusted, to respond, thereby opening the circuit of the operating windin of the main switch. The main switch wou d,"thereupon, become deenergized and open the motor vcircuit, at the same time opening the circuit of the operating winding of the accelerating device. Hence, the arm 4 of the accelerating device would descend, thereby reinserting the resistance S-in the armature circuit, to protect the motor when again started. It Wlll thus be seen, that upon an abnormal increase in voltage the motor is protected by disconnecting the samel'from circuit. operating winding of the relay switch was merely connected across the terminals of the Of course, if the motor armature, the same wouldbecome deenergized and would return to closed position as soon as the motor armature slowed down, thereby decreasing the counterelectromotive force developed thereby. Under such conditions, the relay switch'would tend to automatically restart the motor, regardless-or the voltage conditions of the supply lines. That is to say, the relay might cause the motor to be restarted before the voltage of the main line was restored to a safe value. lit will be seen, however, that upon energization of the relay switch, the lamp switch 10 will be opened, thereby disconnecting the relay winding from one terminal of the motor armature, and that a maintainingcircuit is established for the relay winding through the resistance 12. This maintainlng circuit may be traced from main line 13 by conductor 28 through the resistance 12 by conductor 26 through the relay winding by conductors 25 and 21 through the accelerating device to main line 14. The resistance 12 is designed to so reduce the voltage impressed upon the relay winding from the supply circuit, that said relay will not respond, except to an abnormal increase in the voltage at the terminals at the motor armature. Un the other hand, the resistance 12 is so designed as to maintain the relay winding energized, after it has once responded, until the voltage of the supply circuit is reduced to a predetermined safe value.

its the relay switch will respond only to an abnormal voltage at the armature terminals, it is essential that the lamp switch 10 shall not be opened until the core of the irelay winding is moved into such a position that it will be retained by the current traversing the maintaining circuit. Hence, the switch 10 is preferably so arranged, that it will not be opened until the relay switch approaches the limit of its upward movement. With such an arrangement, the switch 10 will close upon initial movement of the relay switch toward normal position. Assuming, now, that the relay switch has responded, the same will be maintained energized until the line voltage is reduced to a predetermined safe value, in accordance with the adjustment. or design of the resistance 12, included in the maintaining circuit. Of course, when the voltage is reduced to the predetermined degree the relay winding will release its plunger, thereby allowing the relay'switch to move toward normal position. Upon initial movement off the relay switch, in this direction the lamp switch 10 returns to'normal position, again connecting the relay Winding across the terminals of the motor armature. Assuming, that in the meantime, the motor has been brought to rest, or slowed down, closure of the lamp switch 10 will practically short-circuit the relay winding through the motor armature,

.prompt return upon reduction of the line voltage to a safe value, and that, therefore,

a relay connected in accordance with my in vention Wlll be very sens tive and eflicient in operation.

With the controller, illustrated, it is apparent that when the motor has once been disconnected from circuit, it cannot be again connected in circuit until normal voltage conditions are restored. Furthermore, it is apparent that upon return of the relay device to normal position, after restoration of normal voltage, the'same will complete the energizing circuit'of the main switch 1, thereby automatically restarting the motor, that is, assuming that the manual control switch 16 has not, in the meantime, been opened. On the other hand, by opening the main switch 1, the motor will be maintained disconnected from circuit, notwithstanding the return of the relay 'to normal position. If the switch '16 is opened while the relay switch is energized, it cannot be further manipulated to restart the motor until the relay has returned to normal position.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a motor controller in combination, electroresponsive protective, means for the motor, 'CIICIllt connections rendering said means res onsive to abnormal voltage conditions in t e motor circuit and other circuit connections for maintaining said means energized after response thereof until normal conditions are restored.

2. In a motor controller in combination, electroresponsive protective means for the motor, circuit connections rendering said means responsive to abnormal electrical conditions in the motor circuit and other circuit connections for maintaining said means energized after response thereof until normal conditions are restored, said first mentioned circuit connections being interrupted upon response of said means.

3. In a motor controller in combination, electroresponsive protective means for the motor responsive upon the occurrence of abnormal electrical conditions in the motor circuit and means rendered effective upon initial movement of said protective means toward normal position to weaken the operating winding. thereof.

4- In a motor controller, in combination, an electroresponsive rotective device for the'motor and means or rendering said device responsive to abnormal electric conditions in the motor circuitand for insuring substantially full deenergization of said device upon initial return movement thereof toward normal position.

5. In a motor controller in combination, an electroresponsive protective means for the motor, an energizing circuit therefor connected across the terminals of the motor armature and a maintaining circuit therefor connected across the supply circuit.

6. In a motor controller in combination, an electroresponsive protective device for the motor, an energizing circuit therefor comprising 'a'loop across the terminals of the motor armature, a switch in said loop 0 ened upon response of said device and cibsed upon the return thereof toward initial position, and a maintaining circuit for said device including connections from one of the supply lines to said loop at a point between said switch and the operating winding of said device.

7. In a motor controller, in combination, an electroresponsive protective device for the motor including an electro-responsive switch and means for rendering said former switch responsive to abnormal electrical conditions in the motor circuit, forinsuring against return thereof to normal osition until restoration of normal e'lectrica conditions and for insurin substantially full deenergization of sai device upon initial movement thereof toward normal position.

8. In a motor controller, in combination, electro-responsive means for effecting disconnection of the motor from circuit and means for rendering said former means responsive to abnormal voltage conditions in the motor circuit, for maintaining said formor means energized after interruption of the motor circuit and for insuring the return of said former means to normal position when the voltage of the supply circuit is decreased'to a predetermined value,

9. In a motor controller in combination, electroresponsive means for effecting disconnection of the motor from circuit upon an abnormal increase in voltage and automatic means controlling said former means to insure against closure of the motor cir-, cuit' until normal conditions are restored and further insuring the restoration of said former means to normal position upon restoration of normal voltage conditions.

10. In a motor controller, in combination, electro-responsive means controlling the continuity of the motor circuit and an electroresponsive control device therefor, said de- .vice being responsive to abnormal electrical conditions to effect disconnection of the motor from circuit and to insure against subsequent connection thereof until normal electrical conditions are restored, said device having automatic control means insuring its delinergization upon restoration of normal electrical conditions.

11. In a motor controller in combination,

'12. In a motor controller in combination,-

an electroresponsive relay device for opening the motor circuit upon an abnormal in crease in the voltage applied to the motor, connections for maintaining said relay device energized after interruption of the motor circuit while abnormal voltage'conditions prevail and means controlled by said device for insuring full return thereof to normal position when the line voltage drops to a predetermined value.

13. In a motor controller in combination, an electroresponsive relay device adapted to respond upon an abnormal increase in voltage to cause the motor to be disconnected from circuit, circuit connections for maintaining said relay device energized while abnormal voltage conditions prevail, and means insuring substantially full deenergization of said relay device upon initial movement of the same toward normal position. a

14. In a motor controller in combination, on electroresponsive relay'device having its operating winding connected across the terminals of the motor armature, said device being adapted to'respond upon an ab normal increase in the voltage applied to the motor for disconnecting the motor from circuit, an auxiliary switch controlled by said relay device for interrupting the energizing circuit of the operating wmding of said device after it has responded, connections for maintaining said device energized until normal voltage conditions are restored, said auxiliary switch being adapted to close upon initial movement of said relay device toward normal position to, substantially short-circuit the operating winding thereof through the motor armature.

15. In a motor controller in combination, an clectrorcsponsive relay, device having its operating winding connected across the terminals of the motor armature to cause said device to respond upon an abnormal increase of voltage to disconnect the motor from circuit, a switch connected in the circuit of the operating winding of said relay device and arranged to be automatically opened after said relay device has'responded and closed upon initial movement of said relay device toward normal position, and cirmosses cuit connections betweenone terminal of the operating windmg of said relay device and one of the supply lines for malntainmg said relay device energized while abnormal voltmal position when normal voltage is re-' stored. J

16. In a motor controller in combination, means for starting the motor, an electroresponsive relay device for causing the motor to be disconnected from circuit upon an abnormal increase in the voltage applied thereto, connections for maintaining said relay device energized after interruption of the motor circuit to prevent restarting of the motor while abnormal voltage conditions prevail, and means controlled by said device for insuring full return thereof to normal position when the line voltage drops to a predetermined value. p

17. In a motor controller in combination, automatic means for starting the motor, an electroresponsive relay device for causing said means to disconnect the motor from circuit upon anabnormal. increase in volt.- age, connections for maintaining said relay device, energized while abnormal voltage conditions prevail, and means controlled by I said device for insuring full return thereof to initial position when the line voltage drops to a predetermined value, to cause said first mentioned means to automatically restart the motor.

18. In a motor controller in combination, electroresponsive means for starting the motor, an electroresponsive relay switch adapted to respond upon an abnormal increase in the voltage applied to the motor to deenergize said first mentioned means to disconnect the motor from circuit, means for maintaining said relay device energized while abnormal voltage conditions prevail and for insuring the full return of said relay switch to normal position when normal voltage is restored, whereby said electroresponsive means will be energized to automatically restart the motor.

19. In a motor controller in combination,

electrorcsponsive means for starting the motor, a relay 'switch having an operating winding connected across the terminals of the motor armature, said relay switch being adapted to respond upon an abnormal increase in the voltage applied-to the motor to deenergize said first mentioned means, an auxiliary switch ope'rated by said relay switch for disconnecting the relay winding from one terminal of the motor armature after the same has responded, a maintaining circuit for maintaining said relay winding energized while abnormal voltage conditions prevail, said auxiliary switch being adapted to close upon initial movement of said relay scribed my name in the presence of two witswiteh towarg noimal position to insure full nesses. return of sai re ay switch to normal bsition when the voltage of the supply ci cuit, CLARENCE EVANS' 5 has been reduced to a predeterminedsafe Witnesses:

value. FRANK H. HUBBARD,

, In witness whereof, I have hereunto sub- GEORGE HAYNES. 

